[Solved]-Unable to create a constant value of type 'WebApplication13.Models.Service'. Only primitive types or enumeration types are supported in this context-LINQ,C#

    public IEnumerable<UserOperator> GetSkillAgents(List<Service> skillsList)
    {
        var guid = "11111111-1111-1111-1111-000000000004";

        from userOperator in _context.UserOperators
        from groupOperator in userOperator.GroupOperators
        from line in userOperator.Lines
        from services_Line in line.Services_Lines
        from skill in skillsList
        where groupOperator.guidGroup.ToString() == guid &&
              skill.guidService == services_Line.guidService
        select userOperator;
    }